There are many types of willow trees that contain various amounts of the active ingredient necessary to make aspirin. You need to know the types of willow trees that contain the most salicylic acid. Review a list of trees to see what is common for your area when you want to learn how to make aspirin.
You only need the bark from a willow tree when you know how to make aspirin. Water is also used for making homemade aspirin. The aspirin is in the form of a liquid just like a tea. Drink a cup or two of the aspirin to alleviate any pain.
Instructions for how to make aspirin in an emergency are available on wikihow.com here….